1. Field of the Invention
The present invention relates to a method and apparatus for the control of pests, such as ants and bees and, more particularly, it relates to the use of micromachines at least partially covered by an attractant and having radio activated switch means which establish responsive battery activation of means which directly or indirectly initiate action to control the pests.
2. Description of the Prior Art
In addition to other pests, such as wasps and bees, there are approximately 10,000 species of ants worldwide. Depending on the species, they nest in the ground, in trees or in man-made structures. Ants feed upon everything humans do in addition to a variety of other items.
Ants can be beneficial in that they attack and kill pests of humans and agricultural crops, play a role in soil aeration, nutrient cycling and topsoil formation, pollinate certain plants, and are a source of human food in certain societies.
However, some ants are harmful to humans. Ants have been found to carry human disease organisms which they spread when they invade hospitals and walk on patients, patients' food and medical preparations. Ants also attack and destroy agriculturally important crops and animals, and reduce populations of native birds and reptiles. Certain ants also tunnel through trees and wooden structural members in homes causing serious structural damage.
All ants are social insects in that they live in colonies containing specialized groups of ants. These groups are the workers, the larvae, the queen, and the males. The queen controls the activities in the nest by emitting chemical signals to the members of the colony.
The workers are sterile females and are the most numerous members of the colony. They perform most of the work of the colony such as constructing the nest, gathering food, feeding other members of the nest, defending the nest, and cleaning the nest. The larvae are grub-like, immature ants that are constantly fed, groomed and protected by the worker ants until they develop into adult ants.
Due to their extremely narrow esophagus, the adult ants (the workers, queens, and males) are generally able to consume only liquid foods. The workers regurgitate some of the liquid food in their stomach to other members of the colony, including the queen. Sharing nourishment in this manner is called trophallaxis.
The larvae (in their later stages of development) are the only members of the colony that can consume solid food. The larvae are fed pieces of solid food which they digest. The larvae then exude certain secretions through their skin which are eagerly licked up by the workers. When the larvae have grown, they go through a period of change called metamorphosis, during which they change from their grub-like form to an adult ant.
After an ant colony has matured, some of the larvae metamorphose into winged, fertile females and males, in addition to workers (sterile females). At the appropriate time, these fertile females and males mate (either in the nest or outside the nest) and the fertilized female, now called a queen, seeks a suitable location to establish a new colony. The male dies shortly after mating. The queen will lay about a dozen eggs which she tends to and feeds until they have developed into adult ants. During this period, the queen does not leave the nest or gather food, but she lives on the nourishment from the stored fat and dissolving wing muscles in her body. She also feeds the first brood of developing larvae by regurgitating some liquid food to them. When the first adult ants hatch, they leave the nest to gather food for themselves and the queen. From this point on, the queen's only function is to increase the population of the nest by laying eggs. The nest grows in size and matures and the cycle is repeated when fertile females and males are produced.
The ability of ants to thrive under a variety of conditions and man's expansion into areas naturally inhabited by ants has brought ant and man into confrontation. Man has employed various means to control ants including pesticidal sprays, dusts, baits, pouring boiling water into an ant mound, and removing food sources. Most recently, use of pheromones to detrimentally alter the behavior of the ants, use of disease organisms to kill the members of the ant colony, and use of natural insect enemies of ants are being researched and used to control ants. The Florida Department of Agriculture released several thousand Brazilian phorid flies in an attempt to control the fire ant in Florida. However, even with the above control attempts over the years, ants continue to thrive and cause damage. A primary reason for this is that the ant colony, and in particular, the queen and developing larvae, being below ground, in a tree limb, or inside the wall of a home, are hidden from view and protected. In most cases, unless the queen and developing larvae are destroyed, the ant colony can regenerate to its pretreatment population levels in a short period of time. Therefore, the key to greater control of ants is being able to deliver an ant-controlling substance deep into the nest where the queen and developing larvae reside or being able to locate the queen and developing larvae so they can be treated and eliminated by conventional means, such as spraying with an insecticide.
The fire ant is believed to have been introduced into the port of Mobile, Ala. in the 1930's, most likely in soil used as ballast on South America cargo ships. The fire ants spread from Mobile to other areas across the southern United States. Spread of the fire ants is due not only to natural mating flights, but also to the movement of infested plants, sod, and soil. In 1958, the Federal Fire Ant Quarantine was enacted to try to prevent the spread of fire ants from quarantined areas, but the ant continues to spread at the rate of 5-12 miles per year. Eventually fire ants, unless controlled, are expected to infest almost one-fourth of the United States, including the western seaboard where temperature and moisture are adequate to support establishment of the fire ants. Northward spread of fire ants has been limited by cold weather, but colonies can survive in northern areas by building their nests under roadways, against concrete slabs and in external walls of heated buildings.
The mound or nest of the fire ants has no external openings; underground tunnels radiating from the mound allow ants to come and go in search of food. The number of ants determines the size and growth of each colony. Beginning colonies are generally a few inches across, compared to older colonies which may be in excess of two feet or more in height and diameter. The mound is a series of interlocking tunnels and chambers which may reach more than five feet below the surface. Where the ants are located within the nest is dependent on weather conditions, water level and other factors.
Fire ants are best known for their aggressive behavior. If their nest is disturbed, they defend it by swarming out and over the mound, even running up grass blades and sticks.
Workers of many different sizes make up the fire ants colony. The largest workers are called majors; the medium-sized workers are called medias; and the smallest workers are minors. However, the age of the worker ant, not her size, determines what tasks she will eventually perform.
A mature fire ant colony may contain 100,000 to 500,000 workers and several hundred winged males and females that remain in the nest until weather conditions are favorable for mating flights. After mating in the air, the new queen falls to the ground to begin a new colony, and the male falls to the ground and dies.
Eggs of the fire ant hatch in 7-10 days into grub-like larvae. Larvae are totally dependent on workers for their care. During the following 6-12 days, the larvae will molt four times. After the fourth molt, larvae become pupae and go through metamorphosis. Adults emerge in 9-16 days and begin their tasks in the colony. The oldest ants in the colony are the "foragers." They are responsible for locating food to feed the colony. When a food source is found, the foragers lay a chemical trail back to the mound where they recruit other ants to help transport the food back to the colony.
Fire ant colonies need large amounts of carbohydrates, proteins and fats for their development. They get most of their carbohydrates from eating plant sap and most of their proteins and fats from eating dead animals or those they kill. Fire ants are especially fond of insects. Fire ants may chew and extract liquids from the food source immediately or they may bring the food particle back to the mound where it is given to the largest larvae, the only stage of the fire ant life cycle that can digest solid food.
The fire ant queen controls colony growth and activity by the secretion of chemicals that are licked off of her and passed from worker to worker. Certain workers shield the queen from danger by consuming foods before they are fed to her and by quickly carrying her away if the mound is disturbed. The colony can endure as long as the queen and a few workers survive. This guarding of the queen makes eliminating a fire ant colony very difficult.
Fire ant colonies may include one or more queens. Single queen colonies are very territorial toward other fire ants. Newly mated queens landing in the territory of a single queen colony are attacked and killed. Colony life is different in multiple queen fire ant colonies. Workers in these colonies are less aggressive toward workers from other mounds, therefore, mounds are closer together, making those areas more heavily infested. In multiple queen sites, newly mated queens are often accepted into the colony instead of being killed. Multiple queen colonies may contain a few queens or up to several hundred. Control of these colonies is challenging, because as long as one queen survives, the colony can continue.
The aggressive behavior of fire ants and the ability of each worker to sting repeatedly threatens both man and animal. The sting injects a venom that causes an extreme burning sensation. Pustules, which can become infected if scratched, form. Allergic reactions of people sensitive to the venom include dizziness, swelling, shock and in extreme cases, unconsciousness and death. People exhibiting such symptoms should see a physician. Each year, fire ants do an estimated $300 million in damage in Texas alone. This figure includes pesticide purchases, medical expenses, equipment repair, and livestock losses in rural areas. Fire ants also cause loss of use of public parks and playgrounds, damage to roadway structures, and an indeterminable amount of damage to the environment and local ecosystems. Due to fire ants, Texas has lost a large amount of ground-nesting birds such as quail, doves, and pheasants.
A population of native ants is one of the few factors that can slow the invasion of fire ants. Newly mated fire ant queens, before burrowing into the ground, are susceptible to being killed by native ants. Therefore, it is important to consider the preservation of native ant species when applying fire ant control measures.
Eradication of imported fire ants is difficult using present day pesticides because of 1) the large area of infestation, 2) the relatively small area that can be treated with pesticides, 3) short residual activity of current pesticides, and 4) the rapid recolonizing rate of treated areas. Introducing pheromones or disease organisms into the fire ant nest would be an efficient way to control the fire ants, but until the present invention there was no effective way to get the pheromones or disease organisms deep into the nest where the queen and developing larvae reside.
Winged male and female black carpenter ants, called swarmers, emerge from mature colonies usually from March to July. After mating, males die and newly fertilized females (mated for life), now called queens, establish a new colony in a small cavity in moist wood such as a tree stump, fire wood stored near a home, or a wooden porch moistened by rain. The queen lays 15 to 20 eggs in 15 days and feeds the larvae that hatch from the eggs with a regurgitated fluid. The queen does not take food, but uses her stored fat reserves and her wing muscles for her nourishment. The carpenter ants egg stage takes about 24 days, the larval stage 21 days, and the pupal stage 21 days for a total of about 66 days from egg to adult at a temperature of 70 to 90 degrees F. Cool weather may lengthen this period up to 10 months. The few workers emerging from the first brood assume duties of the colony, collecting food, excavating galleries to enlarge the nest and tending the eggs, larvae and pupae of the second generation. Workers regurgitate food for nourishment of the developing larvae and the queen. The queen's duties now are laying eggs and controlling activities in the nest by secreting chemicals that are sensed by the colony members.
It takes about three years for a carpenter ant colony to mature and produce swarmers. A mature colony, after three to six years, may have about 2,000 to 4,000 individuals. Workers have strong jaws and readily bite when contacted.
Carpenter ant nests are usually established in soft, moist (not wet), decayed wood or occasionally in an existing wood cavity or void area in a structure that is perfectly dry. Workers cut galleries in the wood, expanding the nest size for the enlarging colony. Galleries are irregular, usually excavated with the wood grain (sometimes across the grain) into softer portions of the wood. The walls of the nest are smooth and clean (sandpapered appearance) with shredded sawdust-like wood fragments, like chewed up toothpicks (frass), carried from the nest and deposited outside. These piles of wood fragments, often found beneath special openings (windows) or nest openings, may contain indigestible food items such as portions of insects and empty seed coats.
Carpenter ants do not eat wood, but excavate wood galleries in which to rear their young ants. The food diet is of great variety (omnivorous) consisting of both plant and animal materials such as plant juices, fresh fruits, insects (living or dead), meats, syrup, honey, jelly, sugar, grease, fat and "honey dew" (aphid excrement), for example. They feed readily on termites and usually never coexist with them in a home. Workers are known to forage for food as far as 100 yards from their nest.
Carpenter ants may establish nests in a number of different locations. It is important to realize that these locations can be either inside the walls of a home or outside the home in a tree stump. Carpenter ants actually construct two different kinds of nests: parent colonies which, when mature, contain an egg-laying queen, brood and 2,000 or more worker ants, and satellite colonies which may have large numbers of worker ants, but no queen, eggs or young larvae. The carpenter ants found inside a person's home may have originated from the parent colony or from one or more satellite nests.
Control of carpenter ants necessitates locating the site of the nest and treating it with pesticide or otherwise destroying it. Locating the exact position of the nest is often difficult because the point of entry of a single carpenter ant may be 10 feet or more from the nest. If carpenter ants are seen entering a hole in the wall of a home, they may travel many feet behind the wall before reaching the nest. Therefore, treatment of the entry hole or the immediate vicinity around the entry hole may not reach the nest where the queen resides. The difficulty in controlling carpenter ants is reflected in a survey of pest control operators (PCO) that provide carpenter ant service. The survey revealed that 50% of the carpenter ant jobs performed required return visits and additional treatment.
Another method of controlling carpenter ants involves the use of baits. A favorite food material of carpenter ants, such as certain insect larvae and pupae, are ground and mixed with a slow-acting toxicant and then formulated into small granules that the carpenter ant can pick up. A PCO spreads the small bait granules around the vicinity of the carpenter ants nest where carpenter ants have been seen foraging. The carpenter ants pick up and bring the granules into the nest where the granules containing the toxicant are fed to the larvae. The worker ants may also crush the granules and swallow any liquid that may ooze from the granules. The slow-acting toxicant is then spread through the colony by trophallaxis and the colony may eventually be eliminated. However, the use of baits requires weeks to months to take effect and may require repeat applications. Also, the effectiveness of baits is reduced when there are competing food sources for the carpenter ants.
U.S. Pat. No. 4,874,611 discloses the use of a microencapsulated ant bait wherein a core is said to contain an attractant such as soybean extract mixed with an insecticide. An outer shell is formed over the core. The shell is said to have adequate strength and water resistance while permitting penetration by insects.
U.S. Pat. No. 5,527,531 discloses a system for delivery of biologics or chemicals to wild animals such as raccoons, dogs or foxes. A waterproof capsule which contains the material desired to be delivered is embedded in synthetic bait which serves as an attractant. A sleeve made of sponge material, for example, may be employed over the capsule and provided with the food attractant.
In spite of the foregoing prior art disclosures, there remains a very real and substantial need for a method and apparatus of effectively controlling ants and other pests, such as wasps and bees, so as to destroy them or interfere with their ability to procreate.